Sautee the white bulb of the leek with 1.5 tablespoons of olive oil. Add in the chopped fennel. Sauté for 5 minutes. Add in the green of the leek and the zucchini slices and sauté. Meanwhile, toast walnuts in a skillet or under the broiler. Add them into a medium bowl with garlic, lemon juice, 1.5 tablespoons of olive oil, parsley and salt and pepper. Mix well. Once sauté mix has reached the desired tenderness, mix the warm vegetables into the bowl with all of the other ingredients. Serve as a side dish.